(19) |
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(11) |
EP 0 106 615 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
|
25.07.1984 Bulletin 1984/30 |
(43) |
Date of publication A2: |
|
25.04.1984 Bulletin 1984/17 |
(22) |
Date of filing: 03.10.1983 |
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(84) |
Designated Contracting States: |
|
BE CH DE FR GB IT LI NL SE |
(30) |
Priority: |
07.10.1982 GB 8228728
|
(71) |
Applicant: AMERSHAM INTERNATIONAL plc |
|
() |
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|
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(54) |
Assay for the free portion of substances in biological fluids |
(57) @ An assay for the free portion of an analyte, present in a biological fluid which
also contains the analyte bound to natural binders, comprises incubating a sample
of the fluid with a specific binder for the analyte and an antibody to the specific
binder whereby the analyte and the antibody are caused to compete for binding sites
on the specific binder. The antibody is preferably an anti-idiotype antibody to the
specific binder. One of the specific binder and the antibody is labelled, whereby
the proportion of the labelled reagent bound to its binding partner can be measured
and used to determine the free analvte concentration in the samole.